Lydia Longacre was best known for her miniatures and portraits paintings.
Elected Artist to the Lyme Art Association in 1916; exhibited in Old Lyme 1911-1951 at Phoebe Griffin Noyes Library and Lyme Art Association Gallery; student of William Merritt Chase and H. Siddons Mowbray at Art Students League of New York; student of James MacNeil Whistler in Paris; father Andrew Longacre engraver and watercolorist; sister Breta Longacre (1887-1923) painter who exhibited in 15th and 16th Annual Exhibitions in Old Lyme.
Lydia exhibited with the American Society of Miniatuer Painters, whose Levantia White Boardman Award for best miniature she received in 1949, and with the Old Lyme Art Association in Connecticut. She died in Old Lyme, and is buried in the family plot at Philadelphia's Woodland Cemetary. Longacre is represented in the collection of the Smithsonian Museum by a miniature portrait of Rosina Cox Boardman, a watercolor on ivory dating to 1937;a miniature portrait in the same medium of fellow Old Lyme artist, Bruce Crane, painted in 1931, is owned by the Metropolitan Museum of Art.Four of her paintings are currently among the holdings of Old Lyme's Florence Griswold Museum.